From: Jan Kara <jack@suse.cz>
Date: Wed, 15 May 2019 08:57:40 +0200
Subject: [PATCH] block: Don't revalidate bdev of hidden gendisk
References: bsc#1120091
Patch-Mainline: v5.2-rc3
Git-commit: 31cb1d64da4ebd214348cad9d86e663c831c45fc

When hidden gendisk is revalidated, there's no point in revalidating
associated block device as there's none. We would thus just create new
bdev inode, report "detected capacity change from 0 to XXX" message and
evict the bdev inode again. Avoid this pointless dance and confusing
message in the kernel log.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.com>
---
 fs/block_dev.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 53463e801387..bed1bb569409 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1361,20 +1361,27 @@ EXPORT_SYMBOL(check_disk_size_change);
  */
 int revalidate_disk(struct gendisk *disk)
 {
-	struct block_device *bdev;
 	int ret = 0;
 
 	if (disk->fops->revalidate_disk)
 		ret = disk->fops->revalidate_disk(disk);
-	bdev = bdget_disk(disk, 0);
-	if (!bdev)
-		return ret;
 
-	mutex_lock(&bdev->bd_mutex);
-	check_disk_size_change(disk, bdev, ret == 0);
-	bdev->bd_invalidated = 0;
-	mutex_unlock(&bdev->bd_mutex);
-	bdput(bdev);
+	/*
+	 * Hidden disks don't have associated bdev so there's no point in
+	 * revalidating it.
+	 */
+	if (!(disk->flags & GENHD_FL_HIDDEN)) {
+		struct block_device *bdev = bdget_disk(disk, 0);
+
+		if (!bdev)
+			return ret;
+
+		mutex_lock(&bdev->bd_mutex);
+		check_disk_size_change(disk, bdev, ret == 0);
+		bdev->bd_invalidated = 0;
+		mutex_unlock(&bdev->bd_mutex);
+		bdput(bdev);
+	}
 	return ret;
 }
 EXPORT_SYMBOL(revalidate_disk);
-- 
2.16.4